Organocatalytic Ring-Opening Polymerization of N-Acylated-1,4-oxazepan-7-ones Toward Well-Defined Poly(ester amide)s: Biodegradable Alternatives to Poly(2-oxazoline)s
KAUST DepartmentPhysical Sciences and Engineering Division, KAUST Catalysis Center, Polymer Synthesis Laboratory, King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia
Chemical Science Program
KAUST Catalysis Center (KCC)
Physical Sciences and Engineering (PSE) Division
Embargo End Date2021-03-18
Permanent link to this recordhttp://hdl.handle.net/10754/662209
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AbstractWe report a series of poly(ester amide)s (PEAs) synthesized by organocatalytic ring-opening polymerization (ROP) of N-acylated-1,4-oxazepan-7-one (OxP) monomers, produced from Nacylated-4-piperidones using the Baeyer−Villiger oxidation reaction. The ROP of OxPs, conducted in CH2Cl2 at room temperature with benzyl alcohol as initiator and TBD/TU (1,5,7-triazabicyclo[4.4.0]dec5-ene/thiourea) as a binary organocatalytic system, revealed a controlled/living character. The thermodynamics of the ROP highly depends on the N-acylated substituent of monomers, with the following reactivity order: OxPPh > OxPMe > OxPPr > OxPBn. Based on NMR results, it seems that our system follows the hydrogen bonding bifunctional activation mechanism. All intermediates and final products were characterized by NMR, MALDI-TOF MS, SEC, and DSC techniques. All poly(N-acylated-1,4-oxazepan-7-one) (POxP) polymers are amorphous with different glass transition temperatures (Tg), depending on the N-acylated substituent (Tg: −2.90 to 43.75 °C). Among the synthesized polymers, only POxPMe was water-soluble and it degraded much faster than polycaprolactone in an aqueous phosphate buffer saline solution (pH = 7.4). Therefore, poly(N-acylated-1,4-oxazepan-7-one)s are potential biodegradable alternatives to poly(2-oxazoline)s.
CitationWang, X., & Hadjichristidis, N. (2020). Organocatalytic Ring-Opening Polymerization of N-Acylated-1,4-oxazepan-7-ones Toward Well-Defined Poly(ester amide)s: Biodegradable Alternatives to Poly(2-oxazoline)s. ACS Macro Letters, 464–470. doi:10.1021/acsmacrolett.0c00040
SponsorsThe research reported in this publication was supported by King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.
PublisherAmerican Chemical Society (ACS)
JournalACS Macro Letters